1. Field of the Invention
The present invention relates to a technique for defining subscriber attributes in a cell switching system such as an ATM switching system, etc.
2. Description of the Related Art
In recent years, the organizations such as the ITU-T, ATM Forum, etc. have been standardizing the ATM switching system (Asynchronous Transfer Mode), which is a technique for implementing a wide area ISDN (Integrated Services Digital Network).
A representative of switching connection systems implemented with the ATM switching system is an SVC (Selected Virtual Connection) system. With the SVC system, a subscriber specifies a destination address when he or she desires to make a communication in a similar manner as with a telephone, so that a relay path is selected to dynamically establish a virtual connection, and the virtual connection is released when the communication is terminated. Since a communication path can dynamically be selected depending on a location or state of a party, or a state of a network using the SVC system, the network can be used more efficiently.
With the SVC system, the information called subscriber attributes must be defined for each subscriber, in order to implement switch connection control, accounting control, etc. of each subscriber. The subscriber attributes include a subscriber accommodation location number, maximum connectable virtual connection number, maximum obtainable bandwidth value, connectable service class type, congestion regulation class, presence/absence of a use of a subaddress, presence/absence of a use of information about a lower layer, presence/absence of a transfer of information about a higher layer, presence/absence of an address screening and a screening list, and control information about an accounting information collection, etc.
Conventionally, a user network interface (UNI) used a physical subscriber line such as an optical fiber, as an assignment unit for a subscriber line. Accordingly, the subscriber attributes are defined in physical subscriber line units.
With the ATM switching method, a subscriber can realize a high-speed communication at a maximum transfer rate of several-hundred-M bps due to the advancements in optical fiber technology. Additionally, an entire bandwidth is divided into a plurality of virtual paths (VPs), so that the subscriber can realize a communication in a form in which various types of media information are put into cells and are integrated, with the ATM switching system.
However, since the subscriber attributes are defined only in physical subscriber line units, the flexibility of the ATM switching system cannot be fully applied.
Such a problem is remarkable when a subscriber is accommodated in an ATM switch on a network side via a virtual path multiplexer (VP-MUX), and the attributes of each type of media information included in the subordinates to the VP-MUX are recognized as the same attributes in the ATM switch.